title: Polymyxin B treatment improves bactofection efficacy and reduces cytotoxicity.
abstract: Improvements to bacterial vectors have resulted in nonviral gene therapy vehicles that are easily prepared and can achieve high levels of transfection efficacy. However, these vectors are plagued by potential cytotoxicity and immunogenicity, prompting means of attenuation to reduce unwanted biological outcomes while maintaining transfection efficiency. In this study, listeriolysin O (LLO) producing Escherichia coli BL21(DE3) strains were pretreated with polymyxin B (PLB), a pore-forming antibiotic, and tested as a delivery vector for gene transfer to a murine RAW264.7 macrophage cell line using a 96-well high-throughput assay. PLB treatment resulted in statistically significant higher levels of gene delivery and lower cytotoxicity. The results suggest a fine balance between bacterial cellular damage, heightened gene and protein release, and increased mammalian cell gene delivery. Overall, the approach presented provides a simple and effective way to enhance bacterial gene delivery while simultaneously reducing unwanted outcomes as a function of using a biological vector.
authors.affiliation: Department of Chemical and Biological Engineering, University at Buffalo, State University of New York , Buffalo, New York, 14260-4200 United States.
authors.forename: Charles H
authors.initials: CH
authors.lastname: Jones
authors.forename: Snehal
authors.initials: S
authors.lastname: Rane
authors.forename: Emily
authors.initials: E
authors.lastname: Patt
authors.forename: Anitha
authors.initials: A
authors.lastname: Ravikrishnan
authors.forename: Chih-Kuang
authors.initials: CK
authors.lastname: Chen
authors.forename: Chong
authors.initials: C
authors.lastname: Cheng
authors.forename: Blaine A
authors.initials: BA
authors.lastname: Pfeifer
mesh_terms: D000818:Animals; D001427:Bacterial Toxins / Q000378:metabolism*; D002460:Cell Line; D004926:Escherichia coli / Q000187:drug effects / Q000378:metabolism; D015316:Genetic Therapy; D006360:Heat-Shock Proteins / Q000378:metabolism*; D006460:Hemolysin Proteins / Q000378:metabolism*; D006801:Humans; D051379:Mice; D011112:Polymyxin B / Q000494:pharmacology*
chemical_list: D001427:Bacterial Toxins; D006360:Heat-Shock Proteins; D006460:Hemolysin Proteins; D011112:Polymyxin B; C038705:hlyA protein, Listeria monocytogenes